Pretty hard to make money off the pennies.. that 0.12 cents has to pay for transport and the cost of the smelting. After that, you have to consider that an american coin isnt pure metal. A penny is actually a sandwich of copper and zinc in the core, like an oreo. Zinc might actually be more expensive than copper, but it burns off(boils) at a lower temperature than copper melts at, so it is lost. So suddenly, your 1.12 cent penny is worth... 0.37 cents. You also lose some mass to oxides.
Nickle is nickle clad around copper, but the boiling temp of copper is much higher than the melting temperature of nickel, but you would still have to separate the two.